New ext4 vs XFS benchmarks using Fedora 11 Leonidas

What a difference a kernel rev and/or distribution make. If you recall from a previous post, I was unable to complete postmark testing on Ubuntu 9.04 using ext4, and had to recommend against ext4. Now, with the release of Fedora 11 “Leonidas”, a new kernel seems to make a big difference in performance and stability of ext4.

Some other observations before I show any numbers:

This is NOT the same computer as was used in the previous test, don’t use these numbers to compare between Ubuntu and Fedora. It’s a desktop with a 64-bit Athlon and 1GB RAM. I know, I know… I didn’t have access to the other box. Look at Phoronix.com for a comparison of the two.

The 2.6.29 kernel seems to have a much better implementation of the CFQ I/O elevator, I only noticed a slight decrease in performance using deadline instead of the increase I usually get with XFS (ext3 and ext4 have always been tuned for CFQ).

In this version, using my usual (and sometimes unsafe and daring) mount switches didn’t seem to make a huge difference on XFS and none in ext4 or even ext3, Fedora 11 is really a distribution that the developers want you to be able to use without much fussing.

On all tests, I created XFS with mkfs.xfs -f -l lazy-count=1 -l size=128m /dev/… – this enables the 2 main (and safe) tunings that I believe everyone should follow with XFS. Kinda hard to do while installing a distribution, the Fedora 11 installed wasn’t happy about it. Ubuntu is more forgiving, it lets you boot into the LiveCD and you can manually create partitions before you let the installer do its thing. Convenient for single-root-partition installs…

“XFS tuned” means mounted with noatime,logbsize=256k,nobarrier (nobarrier is unsafe unless you’re on a UPS and/or have enterprise back end storage).

“ext3 tuned” means barrier=0,noatime,data=writeback. Used to make a big difference…

The same disk area was used for all tests

Scribefire on Firefox sucks compared to Mac- or Windows-based offline blog editors. There are some KDE-based ones but I didn’t want to download 100s of MB of KDE support infrastructure to run a 600K blog program…

6 Replies to “New ext4 vs XFS benchmarks using Fedora 11 Leonidas”

I’ll be going with XFS as well. Why take a chance with ext4, when XFS is so fast and mature. The fact that the ext4 team postponed releasing the online defragment utility blows away the incentive to switch.

Plus why take a chance that my production systems might lose data with an unfinished release of ext4. For example ext4 can blank out files that have not been undated from the journal during a power fail or unclean shutdown (instead of leaving the data of old version of the file intact; i.e. PERMANENT DATA LOSS); this is due the way theodore tso implemented delayed allocation and his the EXT journaling algorithm.

I’ve been using XFS, both at home and in production at work, since 2002 and I have to say that EXT4 will have to really nail home the numbers in order to convince me to change. The maturity, and the market in which it matured (various higher end SGI servers, US military and various others) and the fact that XFS has saved my ass more than once in the past are all compelling reasons to stick with it. I’ll be keeping an eye on EXT4, but it has a ways to go before i would actually make the move.